Vehicle spring brakes having reduced length
A vehicle spring brake having a parking brake housing that defines a parking brake chamber and a service brake housing that defines a service brake chamber. A flexible membrane separates the parking brake chamber from the service brake chamber and flexes into and out of the service brake chamber based upon a pressure differential between an air pressure in the parking brake chamber and an air pressure in the service brake chamber. A pushrod extends out of the service brake housing when the flexible membrane flexes into the service brake chamber and retracts into the service brake housing when the flexible membrane flexes back out of the service brake chamber. A control valve controls the pressure differential to thereby control movement of the flexible membrane and the pushrod.
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The present application is based on and claims priority to U.S. Provisional Patent Application Ser. No. 62/459,715 filed Feb. 16, 2017, the disclosure of which is incorporated herein by reference.
FIELDThe present disclosure relates to vehicle spring brakes having reduced length.
BACKGROUNDThe following U.S. Patents are incorporated herein by reference in entirety.
U.S. Pat. No. 5,829,339 discloses a sealed bushing assembly adapted to permit a push rod to pass through an adapter isolating a pressurized chamber, formed by attaching a sleeve to the adapter, inserting a bushing, and crimping the end of the sleeve opposite said adapter to restrain the bushing.
U.S. Pat. No. 6,314,861 discloses a diaphragm-based spring brake actuator assembly which allows for the delivery of more force to the push rod without increasing the size of the actuator unit. A stronger heavy main compression spring located in the emergency brake chamber provides greater emergency or parking brake force to the push rod, and a service brake chamber operates more efficiently when braking pressure is introduced. A large pressure plate is positioned inside either the emergency housing or the service brake housing, or both, to deliver more force to the push rod of the actuator.
U.S. Pat. No. 9,050,958 discloses a rotationally adjustable brake actuator includes a pressure housing with a circumferential rim, a non-pressure housing having a second circumferential rim, and a diaphragm disposed there between. A retaining ring holds the respective housings against each other such that the first rim abuts the second rim, but where the respective housings are able to be rotated with respect to the other. Further, the retaining ring includes a radially-oriented hole and a stop pin that is inserted into the hole and engages the pressure housing to prevent further rotation.
U.S. Pat. No. 9,297,392 discloses a pneumatic actuator includes a housing defining a chamber. A diaphragm is positioned within the chamber. A rod member is attached to the diaphragm and is movable between a first position and a second position. A cam member is attached to the diaphragm and to the rod member. The cam member has a cam surface. A deflection rod has a first end portion and a second end portion, where the first end portion of the deflection rod is attached to the housing. A follower is attached to the second end portion of the deflection rod. The follower engages the cam surface of the cam member so as to urge the rod member towards the second position.
SUMMARYThis Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
In certain examples, a vehicle spring brake having a parking brake housing that defines a parking brake chamber and a service brake housing that defines a service brake chamber. A flexible membrane separates the parking brake chamber from the service brake chamber and flexes into and out of the service brake chamber based upon a pressure differential between an air pressure in the parking brake chamber and an air pressure in the service brake chamber. A pushrod extends out of the service brake housing when the flexible diaphragm flexes into the service brake chamber and retracts into the service brake housing when the flexible membrane flexes back out of the service brake chamber. A control valve controls the pressure differential to thereby control movement of the flexible membrane and the pushrod.
In certain examples, a vehicle spring brake has a parking brake housing that defines a parking brake chamber and a service brake housing that defines a service brake chamber. A flexible membrane separates the parking brake chamber and the service brake chamber and flexes as a pressure differential between air pressure in the parking brake chamber and air pressure in the service brake chamber changes. A pushrod extends out of the service brake chamber as the flexible membrane flexes in a first direction and retracts into the service brake chamber as the flexible membrane flexes in an opposite, second direction.
In certain examples, a method for operating a vehicle spring brake includes defining a parking brake chamber with a parking brake housing and a service brake chamber with a service brake housing; positioning a flexible membrane between the parking brake housing and the service brake housing such that the flexible membrane separates the parking brake chamber from the service brake chamber. The flexible membrane flexes into and out of the service brake chamber based upon a pressure differential between an air pressure in the parking brake chamber and an air pressure in the service brake chamber. The method can further include positioning a pushrod in the service brake chamber such that the push rod extends out of the service brake housing when the flexible membrane flexes into the service brake chamber and retracts into the service brake housing when the flexible membrane flexes back out of the service brake chamber such that the pushrod applies a braking force on a vehicle when the pushrod extends out of the service brake housing and controlling, with a control valve that is coupled to a vehicle air system, the pressure differential to thereby control movement of the flexible membrane and the pushrod.
Various other features, objects, and advantages will be made apparent from the following description taken together with the drawings.
Examples of the present disclosure are described with reference to the following drawing figures. The same numbers are used throughout the drawing figures to reference like features and components.
In the present description, certain terms have been used for brevity, clarity, and understanding. No unnecessary limitations are to be inferred therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes only and are intended to be broadly construed. The different apparatuses, systems, and methods described herein may be used alone or in combination with other apparatuses, systems, and methods. Various equivalents, alternatives, and modifications are possible within the scope of the appended claims.
The closed end 16 of the service brake chamber 14 defines a hole 18 through which a pushrod 34 extends, and the pushrod 34 is configured to slide back and forth in the hole 18, as further described herein below. An articulation seal 21 maintains an air tight seal between the pushrod 34 and the closed end 16 of the service brake housing 12 at all times, including during axial movement of the push rod 34 along the center axis 24 of the spring brake 1 and/or radial movement of the pushrod 34 which may be caused by other braking system apparatuses or components (not shown) acting on the pushrod 34. In certain examples, the service brake chamber 14 includes at least one mounting stud 22 that extends from an outer surface 25 of the closed end 16 of the service brake housing 12 and is configured to couple the spring brake 1 to a vehicle (not shown).
The mating end 10 of the parking brake housing 4 and the mating end 20 of the service brake housing 12 are coupled together such that the parking brake chamber 6 and the service brake chamber 14 are closed to the surrounding atmosphere. The parking brake housing 4 and the service brake housing 12 each have at least one opening 13 (
A flexible membrane 30 is disposed between the parking brake chamber 6 and the service brake chamber 14 and separates the parking brake chamber 6 from the service brake chamber 14. In certain examples, the flexible membrane 30 is a flexible diaphragm. In use, the flexible membrane 30 can flex into and out of the service brake chamber 14 based upon a pressure differential between the air pressure in the parking brake chamber 6 and the air pressure in the service brake chamber 14. In the depicted example, the flexible membrane 30 includes an outer perimetral edge 32 that is sealed and sandwiched between the mating end 10 of the parking brake housing 4 and the mating end 20 of the service brake housing 12 so that the air in the parking brake chamber 6 remains separated from the air in the service brake chamber 14. The manner in which the flexible membrane 30 is connected to the spring brake 1 can vary from that which is shown.
A control valve 100 (further described herein below) is fluidly coupled to the openings 13 (
A pushrod 34 is positioned in the service brake housing 12 and is configured to extend out of the service brake housing 12 when the flexible membrane 30 flexes into the service brake chamber 14 (see
The pushrod 34 includes an end plate 36 positioned adjacent to the flexible membrane 30 and an elongated shaft 38 that slides back and forth along the axis 24 in the hole 18 defined by the service brake housing 12. As the flexible membrane 30 moves, the shaft 38 articulates and/or slides in the hole 18. In certain examples, the end plate 36 of the pushrod 34 is fixed to the flexible membrane 30 so that the flexible membrane 30 and pushrod 34 move together.
A return spring 40 is disposed in service brake chamber 14 on the pushrod 34 and is positioned between the end plate 36 and the closed end 16. The return spring 40 has a natural resiliency that tends to retract the pushrod 34 into the service brake chamber 14. In certain examples, the return spring 40 biases the end plate 36 of the pushrod 34 against the flexible membrane 30, away from the closed end 16 of the service brake housing 12. In the illustrated example, the service return spring 40 has a first end 41 that contacts the end plate 36 of the pushrod 34 and a second end 42 opposite the first end 41 that contacts the closed end 16 of the service brake housing 12 (e.g. the inner end surface 27 of the service brake housing 12). In operation, movement of the flexible membrane 30 into the service brake chamber 14 compresses the return spring 40 and slides the pushrod 34 along the axis 24, in a direction out of the service brake housing 12. In certain examples, the return spring 40 is coupled to the pushrod 34 and/or the end plate 36.
A parking spring assembly 50 is disposed in the parking brake chamber 6 and moves into and between an extended state (
An air-tight flexible envelope 74 envelops the parking spring assembly 50. The air-tight flexible envelope 74 defines a cavity 75 within and separate from the parking brake chamber 6 that is fluidly separate from the parking brake chamber 6 (i.e. the flexible envelope 74 is air-tight and thus fluidly isolates the cavity 75 from the parking brake chamber 6). In use, increasing the air pressure in the parking brake chamber 6 compresses the air-tight flexible envelope 74 to thereby move the parking spring assembly 50 into the retracted state (
The air-tight flexible envelope 74 is configured to axially expand or lengthen (
A parking spring 70 is configured to extend or expand and retract or compress as the parking spring assembly 50 moves into and between the retracted state (
The parking spring assembly 50 includes end plates 51, 61 that are disposed on opposing sides 71, 72 of the parking spring 70. The parking spring 70 tends to bias the end plates 51, 61 apart from each other such that increasing the air pressure in the parking brake chamber 6 compresses the air-tight flexible envelope 74 and thereby forces the end plates 51, 61 toward each other and against the natural resiliency of the parking spring 70. The end plates 51, 61 include telescoping sleeves 52, 62 that are nested together and can telescopically move with respect to each other as the air pressure in the parking brake chamber 6 increases and/or decreases thereby aiding in alignment of the parking spring 70. The diameter of the sleeves 52, 62 tapers inwardly, as the sleeves 52, 62 extend away from the end plates 51, 61. In certain examples, the end plate 61 is coupled to and/or integral with the closed end 8 of the parking brake housing 4. In certain examples, the air-tight flexible envelope 74 can include grooves or fins (not shown) that separate the closed end 8 of the parking brake housing 4 from the parking spring assembly 50 and allow air to flow between the end plate 61 and the closed end 8 of the parking brake housing 4.
A guide rod 78 is coupled to the closed end 8 of the parking brake housing 4 and is configured to guide the end plates 51, 61 along the axis 24. That is, the guide rod 78 guides the end plates 51, 61 along the axis 24 as the end plates 51, 61, the parking spring 70, and/or the air-tight flexible envelope 74 move (
The spring brake 1 returns to the driving mode (
Referring to
The spring brake 1 returns to the driving mode (
In certain examples, the spring brake 1 and/or the control valve 100 includes a controller (not shown) having a memory and a processor that is configured to control the vehicle air system and the valves of the control valve 100 to change the operational modes described above.
In certain examples, the control valve 100 includes an energy harvesting device (not shown) that converts the exhausted air (via the exhaust port 110) to energy that can be used to power sensors, communication devices, and/or the like.
In certain examples, a method for operating a vehicle spring brake includes defining a parking brake chamber with a parking brake housing and a service brake chamber with a service brake housing; positioning a flexible membrane between the parking brake housing and the service brake housing such that the flexible membrane separates the parking brake chamber from the service brake chamber. The flexible membrane flexes into and out of the service brake chamber based upon a pressure differential between an air pressure in the parking brake chamber and an air pressure in the service brake chamber. The method can further include positioning a pushrod in the service brake chamber such that the push rod extends out of the service brake housing when the flexible membrane flexes into the service brake chamber and retracts into the service brake housing when the flexible membrane flexes back out of the service brake chamber such that the pushrod applies a braking force on a vehicle when the pushrod extends out of the service brake housing and controlling, with a control valve that is coupled to a vehicle air system, the pressure differential to thereby control movement of the flexible membrane and the pushrod. The method can further include positioning a parking spring assembly in the parking brake chamber that moves between an extended state in which the parking spring assembly pushes the flexible membrane into the service brake chamber such that the pushrod extends out of the service brake housing and a retracted state in which the parking spring assembly does not push the flexible membrane into the service brake chamber.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
Claims
1. A vehicle spring brake comprising:
- a parking brake housing that defines a parking brake chamber;
- a parking spring assembly in the parking brake chamber;
- a service brake housing that defines a service brake chamber;
- a flexible membrane between the parking brake chamber and the service brake chamber, wherein the flexible membrane is caused to flex into the parking brake chamber or the service brake chamber based on a pressure differential between air pressure in the parking brake chamber and air pressure in the service brake chamber;
- a pushrod in the service brake chamber that moves with the flexible membrane as the flexible membrane flexes; and;
- a control valve that controls the pressure differential to thereby control movement of the flexible membrane and the pushrod.
2. The vehicle spring brake according to claim 1,
- wherein the parking spring assembly is moveable into an extended state in which the parking spring assembly pushes the flexible membrane toward the pushrod such that the pushrod extends out of the service brake housing.
3. The vehicle spring brake according to claim 2, wherein the parking spring assembly is movable into a retracted state in which the parking spring assembly does not push the flexible membrane, and wherein the parking spring assembly is normally retained in the retracted state by the air pressure in the parking brake chamber.
4. The vehicle spring brake according to claim 3, wherein increasing the air pressure in the parking brake chamber compresses the parking spring assembly into the retracted state and wherein as the air pressure in the parking brake chamber decreases the parking spring assembly moves itself toward the extended state.
5. The vehicle spring brake according to claim 4, further comprising an air-tight flexible envelope that envelops the parking spring assembly; and
- wherein increasing the air pressure in the parking brake chamber compresses the air-tight flexible envelope and thereby compresses the parking spring assembly into the retracted state.
6. The vehicle spring brake according to claim 4, wherein the parking spring assembly comprises a parking spring, and wherein as the air pressure in the parking brake chamber decreases the parking spring naturally extends the parking spring assembly into the extended state.
7. The vehicle spring brake according to claim 6, wherein the parking spring assembly further comprises end plates on opposing sides of the parking spring;
- wherein the parking spring has a natural resiliency that tends to bias the end plates apart from each other; and
- wherein increasing the air pressure in the parking brake chamber compresses the air-tight flexible envelope and thereby forces the end plates toward each other against the natural resiliency of the parking spring.
8. The vehicle spring brake according to claim 7, wherein the end plates have telescoping sleeves that telescope with respect to each other as the air pressures in the parking brake chamber and the spring brake chamber change.
9. The vehicle spring brake according to claim 7, further comprising a guide rod coupled to the parking brake housing and extending into the parking brake chamber, wherein the guide rod guides the end plates along an axis as the parking spring compresses and extends.
10. The vehicle spring brake according to claim 1, further comprising a return spring on the pushrod, and wherein the return spring has a natural resiliency that tends to retract the pushrod into the service brake chamber.
11. The vehicle spring brake according to claim 10, further comprising an end plate on the pushrod, and wherein the return spring is disposed between the end plate and an inner end surface of the service brake housing.
12. The vehicle spring brake according to claim 11, wherein the end plate is fixed to the flexible membrane such that the flexible membrane and the end plate move together.
13. The vehicle spring brake according to claim 1, wherein the pushrod is configured for attachment to a braking apparatus for a vehicle, wherein extension of the pushrod out of the service brake housing causes the braking apparatus to apply a braking force on the vehicle and wherein retraction of the pushrod into the service brake housing causes the braking apparatus to decrease the braking force on the vehicle.
14. The vehicle spring brake according to claim 13, wherein the braking apparatus comprises a brake adjustor and a brake drum.
15. The vehicle spring brake according to claim 1, wherein the control valve decreases the air pressure in the service brake chamber such that the pressure differential changes, the flexible membrane flexes toward the pushrod, and the pushrod extends out of the service brake housing.
16. The vehicle spring brake according to claim 15, wherein the control valve decreases the air pressure in the service brake chamber by exhausting air from the service brake chamber.
17. A vehicle spring brake comprising:
- a parking brake housing that defines a parking brake chamber;
- a service brake housing that defines a service brake chamber;
- a flexible membrane between the parking brake chamber and the service brake chamber, wherein the flexible membrane is caused to flex into the parking brake chamber or the service brake chamber based on a pressure differential between air pressure in the parking brake chamber and air pressure in the service brake chamber;
- a pushrod in the service brake chamber that moves with the flexible membrane as the flexible membrane flexes;
- a control valve that controls the pressure differential to thereby control movement of the flexible membrane and the pushrod;
- a parking spring assembly in the parking brake chamber, wherein the parking spring assembly is movable into and between: an extended state in which the parking spring assembly pushes the flexible membrane such that the pushrod extends out of the service brake housing; and a retracted state in which the parking spring assembly does not push the flexible membrane or push the pushrod out of the service brake housing; and
- a return spring on the pushrod that has a natural resiliency that tends to cause the pushrod to retract into the service brake chamber.
18. A vehicle spring brake comprising:
- a parking brake housing that defines a parking brake chamber;
- a parking spring assembly in the parking brake chamber;
- a service brake housing that defines a service brake chamber;
- a flexible membrane between the parking brake chamber and the service brake chamber, wherein the flexible membrane is caused to flex into the parking brake chamber or the service brake chamber based on a pressure differential between air pressure in the parking brake chamber and air pressure in the service brake chamber; and
- a pushrod in the service brake chamber that moves with the flexible membrane as the flexible membrane flexes.
19. The vehicle spring brake according to claim 18, wherein the flexible membrane flexes in a first direction when the air pressure in the service brake chamber is less than the air pressure in the parking brake chamber, and wherein the flexible membrane moves in an opposite second direction when the air pressure in the service brake chamber is equal to or greater than the air pressure in the parking brake chamber.
20. The vehicle spring brake according to claim 18, further comprising a control valve that controls the air pressure in the parking brake chamber and the air pressure in the service brake chamber to thereby vary the pressure differential.
21. A method for operating a vehicle spring brake, the method comprising:
- defining a parking brake chamber with a parking brake housing and a service brake chamber with a service brake housing;
- positioning a flexible membrane between the parking brake chamber and the service brake chamber, wherein the flexible membrane is caused to flex into the parking brake chamber or the service brake chamber based on a pressure differential between air pressure in the parking brake chamber and air pressure in the service brake chamber;
- positioning a pushrod in the service brake chamber such that the pushrod moves with the flexible membrane as the flexible membrane flexes, wherein the pushrod extends from the service brake housing when the flexible membrane flexes into the service brake chamber such that the pushrod applies a braking force on a vehicle; and
- controlling, with a control valve that is coupled to a vehicle air system, the pressure differential to thereby control movement of the flexible membrane and the pushrod.
22. The method according to claim 21, further comprising positioning a parking spring assembly in the parking brake chamber that moves between an extended state in which the parking spring assembly pushes the flexible membrane into the service brake chamber such that the pushrod extends out of the service brake housing and a retracted state in which the parking spring assembly does not push the flexible membrane into the service brake chamber.
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Type: Grant
Filed: Feb 16, 2018
Date of Patent: Mar 17, 2020
Patent Publication Number: 20180231082
Assignee: TSE Brakes, Inc. (Cullman, AL)
Inventors: Carl Gaufin (Madison, AL), Ryan Fechner (Madison, AL)
Primary Examiner: Thomas W Irvin
Application Number: 15/932,322
International Classification: B60T 17/08 (20060101); F16D 65/28 (20060101); B60T 15/04 (20060101); F16D 125/12 (20120101); F16D 121/14 (20120101); F16D 121/10 (20120101);